Please help.. i need a logic board

I need a logic board for the hard drive listed below.


WD Cavair SE16

mnf date: 01 june 2007


500 GB
WWN: 50014EE20047E71A

there are numbers on the logic board itself… but none that say part number.

E222034 is all i see…

if anyone can help me i’d be much obliged.

I was quoted $850.00 to recover the data off this drive and i simply can’t afford it nor justify it.

I need a less costly remedy…

thanks in advance,


Can you upload a detailed photo of the component side to a file sharing service?

What was the failure symptom?

When you replace the board, be prepared to transplant the 8-pin serial EEPROM chip from patient to donor. This is because the EEPROM stores drive specific calibration data determined at the factory.

The following article will help you identify the components:

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i hope the above links work…

the logic board went dead when i Inadvertently plugged my camera battery charger into the external drive instead of the one that came with the drive.  it was a 13 volt not a 12 volt.  no sound, no smell, no sign of anything bad except a deadly silence.  no spinning.  just a flashing light on the controller.  i would really like to get my stuff back.  thanks for the reply



The following thread should help you:

I suggest you remove the board from the drive with a Torx screwdriver and upload a detailed photo of the component side.

The most likely culprit is a shorted TVS diode.

Here is another thread with more detailed instructions and photos:

It is for a different brand of drive, but the method and principles are the same.

If you need help, let us know.

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Thank you so much for getting back to me.  A few last questions.  Where do I find a replacement logic board to match the one I have?  What are the tolerances between different models?  You know, like, 1968 - 1972 Chevy’s all have the same transmissions.  I’ve been looking on line for a WD5000AAKB Caviar SE16 to no avail.  Do the “Caviar Blue” models have interchangable logic boards?  Can you suggest an outlet for a matching model hard drive or part number for the logic board that I should be looking for?

Thank you again for getting back to me. 


ps i’ll upload the photos of the under belly of the board when i get home tonight…

thanks again…js

See this thread for information about component matching:

However, PCB replacement should be your last option. The fix may be as simple as removing a shorted 12V TVS diode by snipping it out with side cutters. The Seagate discussion that I referenced shows just how easy the solution can be. Two people with no prior knowledge of electronics or multimeters were able to resurrect their broken drives.

Please upload a photo of the component side of your board and I’ll indicate exactly which component to check.

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As always thank you very much for your time.  Please let me know which one of these pesky little buggers is the 12V TVS diode in question and where, perhaps, I might look for a replacement.  Thanks in advance.  It would be so very nice to retrieve the information from this drive.  You can find the link to the photo of the underbelly of my PCB here…



I have identified the relevant components for you:

The faulty diode is TVS12 (D4 on the board). Confirm that it measures zero ohms on a multimeter. If so, then desolder it, or remove it by snipping its pins close to the body with side cutters. The drive will work quite happily without the diode, albeit without protection on the affected supply rail.

One of the zero ohm links (R64 or R67) will probably be open circuit. They should measure zero ohms when good. If one of them is open, then it is because it will have fused when the diode went short circuit. Replace the open link with a piece of wire, or preferably a 2 amp picofuse. Be careful not to introduce solder shorts.

The preamp connector looks a bit dirty. You can gently shine up the contacts with a soft white pencil eraser.

For continued protection you can replace the 12V TVS diode with an SMBJ12A from Farnell, Mouser, or Digikey.

Good luck.

PS. A straight board replacement will most likely fail. This is because the Marvell MCU chip contains calibration data that are unique to your drive.

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That did the trick.  Thank you so much for your time and your attention to detail regarding my personal crisis.  The data salvage company wanted to charge me nearly $900.00 to recover my data.  Essentially they wanted to preform a quadruple bypass when all I needed was a stint.  Not to sound sappy, but you are my faceless, electronic hero.  I recovered my data, made copies on two new drives and set up a network to organize all my personal information.  This episode was indeed a lesson learned. 

Thanks again,


Hello all,

I just read this post and hope you will be able to help me as well. My situation is similar to Jeffree, with a WD2500JB- 00REA0. On power up it spins up. I hear some clicking then spin down right away.

Will the solution detailed above work in my case?

Thanks in advance.


Sorry, your problem is a different one.

The rule of thumb appears to be that, if a drive spins up but is not detected, or if it tries to spin up, then the board is probably OK. Instead the problem is most likely with the head/disc assembly (HDA).

If, OTOH, the drive makes no noise at all, and does not attempt to spin up, then the board is probably faulty.

I would say that your drive is unable to read its servo information, in which case I think your only realistic solution is professional data recovery. :frowning:

However, you could try shining up the preamp contacts on the underside of the board with a soft white pencil eraser.

You may also like to try different orientations for your drive, eg vertical or upside down. This may flush out a loose connection inside the HDA, or a cold solder joint on the flex PCB that attaches to the preamp chip.

fzabkar–Thanks for the quick response. I will try your suggestions  in the following order, but can you give a bit more information regarding the last one.

  • shining up the preamp contacts
  • different orientations
  • cold solder joint on the flex PCB

Again, thanks for your time an attention.


See the oxidised preamp and voice coil connections in this photo:

Use something like this to shine them up:

 I have an external hard drive one of my dj’s could not find the plug so decided to use a universal one except it blew the circuit board on the hard drive, I believe the polarity was switched. I opened the the unit and removed the circuit board from the harddrive (Q6) is melted and a chip diagonal which does not have a number next to it. I have looked all over the web in search of a diagrag of the layout of the circuitboard with no find.  I have 80,000 songs on here along with family photos. Please if someone could help.



I doubt you will find a circuit diagram, unless someone has reverse engineered it.

Can you upload a detailed photo to a file sharing service?

Here they are thanks for taking a interest in helping me I really appreciate it

Thanks Rob

It appears that the Marvell MCU (88i6540, U5) has a burn mark on it:

If that is the case, then this board is beyond DIY repair. When replacing the board, you will most probably need to transplant the serial EEPROM chip (25P40VP) at U12 from patient to donor. This chip stores unique, drive specific calibration data.

The failed components (Q6, L2, and resistor?) in this photo …

… appear to form part of a switchmode regulator. I can’t see for sure, but I suspect that the junction of capacitors C3 and C4, and the resistor, is the Vcore supply (1.2V ?) for the MCU.

Here are direct links to your other photos:

Do you have any clue where I could buy a new circuit board? Thanks again for all your help.

Apart from eBay, there are the forums at HDD Guru and The data recovery professionals will transfer the adaptive data from patient to donor, if you purchase a board from them. However, I hesitate to recommend them, as I have personal “issues” with many of them.

If you are not experienced in soldering, then ask your local TV/AV repair shop.

See this thread:

The OP writes that s/he "took the board to an electronics repair store and for $20 the ROM chip was swapped. "

My drive will spin up, when it first starts and is cool it will be recignised. when it gets warm it will disapear and the computer won’t see it any more. Here are pictures of the label.